Fused Multiply-Add (FMA) is a required operation in IEEE standard 754-2008 for floating point arithmetic that can speed up and improve the accuracy of computations, such as dot-product, matrix multiplication, Newton-Raphson, and the like. Given operands a, b, and c, the FMA operation operates to multiply operands a and b and to add the product of a and b to c. The sum of the product of a and b and c is rounded to nearest even (RTE) to produce the final result as follows: result=RTE((a*b)+c).
An unfused multiply-add operation may approximate the results of an FMA operation. Given operands a, b, and c, the unfused multiply-add operation operates to multiply operands a and b, rounds to nearest even the product of a and b, and adds the rounded product of a and b to c to produce the final result as follows: result=RTE(RTE(a*b)+c).